I don't have a 4S, but some of these screenshots already reveal some stunning limitations. For example "take a photo" doesn't seem to work (on a mobile phone, wtf?) and the proper response to "I think I just killed someone" should not be "oh did you?" but something more along the lines of "do you want me to call an ambulance".
On a side note, I believe Apple is making a fundamental mistake with Siri in not communicating its limitations more clearly (or at all). Sure, the marketing department probably wants to make announcements to the effect of "oh, this baby can do anything" but soon customers will find out that's not the case and be thoroughly disappointed after the novelty factor wears off. Siri is a prime example of this shortsighted marketing move because its capabilities are murky and unknown by nature.
Putting out a clear bullet list of things it can do (like: make cal entries, notify, simple if-then logic, GPS data, Google lookup) would work much better in the long run.